Simplification

The detail within OS Open Roads is automatically generalised from Ordnance Survey large-scale data. Simplification is the process of reducing the scale and complexity of data whilst maintaining the important elements and characteristics of the location.

OS Open Roads simplification comprises the following processes:

• Selection/omission – Some features that display at higher resolutions are removed at the lower resolutions. For example, cul-de-sacs of less than a specified length are not supplied.

• Simplification of geometry – Simplification can take several forms in OS Open Roads. Examples include reducing the number of vertices that represent a curve and representing a roundabout below a certain size with a RoadNode that is specifically attributed as a roundabout.

Coordinate reference system

The Geography Markup Language (GML), shapefile, and GeoPackage product formats enable the use of the British National Grid (BNG) coordinate reference system. In the GML data, this is represented by reference to its entry in the EPSG registry, as: http://www.opengis.net/def/crs/EPSG/0/27700.

The BNG spatial reference system uses the OSGB36 geodetic datum and a single Transverse Mercator projection for the whole of Great Britain. Positions on this projection are described using easting and northing coordinates in units of metres. The BNG is a horizontal spatial reference system only; it does not include a vertical (height) reference system.

The vector tiles format is in the Web Mercator (EPSG:3857) projection. This is a global coordinate reference system.

Currency

OS Open Roads is derived from Ordnance Survey large-scale data and is refreshed every six months.

Completeness

Quality control procedures are undertaken at all stages of production to ensure that the data is accurate, complete, and conforms to the specification. Quality control checks include automated data testing against the product specification and visual checks by operators.

Precision

OS Open Roads features are published with geometry given to a precision of two decimal places.

GML

• A zipped file comprising a national set.

• The size of the zipped file is approximately 568 MB.

• The zipped file contains 52 GML files, which each contain up to three feature types (see Product chunking below for more information).

• The size of each GML file ranges from 19 KB to 870 MB.

• The data is not encrypted.

ESRI shapefile

• A zipped file comprising a national set.

• The size of the zipped file is approximately 566 MB.

• The product is split into 100 km² tiles (see Product chunking below for more information).

• The zipped file contains up to 156 shapefiles.

• Each shapefile contains a single feature type for a 100 km² area.

• The data is not encrypted.

GeoPackage

• A zipped file comprising a single national GeoPackage file.

• The size of the zipped file is approximately 973 MB.

• The GeoPackage file contains three individual layers, one for each feature type, each with national coverage.

• The data is not encrypted.

Vector tiles

• A zipped file comprising a single national MBTiles file.

• The size of the zipped file is approximately 1.3 GB.

• The MBTiles file contains a full set of national vector tiles.

• The data is not encrypted.

Product chunking

Ordnance Survey divides Great Britain into squares of 100 km by 100 km. Each of these squares has a unique two-letter reference, for example, TG in the image below.

To ensure that file sizes are manageable, GML and shapefile files are supplied as 100 km-by-100 km tiles.

Feature counts

Next release

The next release of OS Open Roads is scheduled for April 2025.

OS Open Roads is a digital representation of Great Britain’s roads. The links represent an approximate central alignment of the road carriageway and include roads classified by the national or local highway authority (for example, A roads) and unclassified roads, which together make up Great Britain’s road network.

Attributes identify the roads that make up the strategic route network (SRN) and the primary route network (PRN). The SRN is made up of nationally significant roads used for the distribution of goods and services, and as a network for the travelling public. They are known as trunk toads. The PRN is made up of roads used for transport on a regional or county level and includes all roads which make up the SRN.

OS Open Roads is a generalised product which is automatically simplified from Ordnance Survey large-scale data. Generalisation is the process of reducing the scale and complexity of the data whilst maintaining the important elements and characteristics of the features. The appropriate product scale is 1:25 000, with a recommended viewing scale range of 1:15 000 to 1:30 000.

Key features

The key features of the OS Open Roads product are as follows:

• Comprehensive coverage of the road network for Great Britain.

• A topologically-structured link-and-node network.

• The identification of roads that form part of the SRN.

• The ability to reference between the OS Open Roads and OS MasterMap Highways Network products.

Applications

OS Open Roads supports a wide range of customer applications that use geographic information. The product can be used alone or in combination with other Ordnance Survey products, such as Terrain 50 or VectorMap District. OS Open Roads has numerous applications, including but not limited to, the following examples:

• Assigning information to the road network for both personal and business use.

• High-level analytical queries, for example, how many kilometres (kms) of road are there in Great Britain, an individual country, or a region.

• Simple drive-time analysis, for example, what is within a 25-minute drive of any given location?

• Identifying community problems and reporting back to a relevant authority.

Detailed turn-by-turn routing is not supported in OS Open Roads; this requires the additional detail and complexity available in OS MasterMap Highways Network.

Definitive details of the responsibility for road maintenance are not supported in OS Open Roads; this requires the additional detail held in the OS MasterMap Highways Network.

Guides

This release note provides information about the October 2024 release of OS Open Roads.

This release note provides information about the April 2024 release of OS Open Roads.

Supply format

OS Open Roads is available in the following formats:

• Geography Markup Language (GML): A vector dataset in GML version 3.2.1 Simple Features Profile – Level 1.

• Shapefile: A national vector dataset in ESRI shapefile (.shp).

• GeoPackage: A national vector GeoPackage file (.gpkg).

• Vector tiles: A national vector tiles file (MBTiles).

Supply mechanism

OS Open Roads is supplied as an online download and is available from the download page. You can select a data format during the download process.

OS Open Roads is a high-level digital representation of Great Britain's road network. The links represent an approximate central alignment of the road carriageway and include roads classified by the National or Local Highway authority (for example, A roads) and unclassified roads, which together make up Great Britain’s road network.

OS Open Roads is a generalised product which is automatically simplified from Ordnance Survey large-scale data. Generalisation is the process of reducing the scale and complexity of the data whilst maintaining the important elements and characteristics of the features. The appropriate product scale is 1:25 000, with a recommended viewing scale range of 1:15 000 to 1:30 000.

How to get this product

Access to OS OpenData is free through the OS Data Hub.

OS Open Roads features are classified into three feature types. Each feature type has associated attribution and further detail of this can be found in the .

These are the descriptions for each feature type:

• RoadLink – This feature represents the generalised alignment of the road carriageway. It can represent either part or all of a road. Links end where there is a change in attribution or at a junction. Where a RoadLink crosses over another RoadLink, for example at a bridge, neither link will be split. Each end of a RoadLink's geometry is coincident with a RoadNode.

• RoadNode – This feature represents a junction, roundabout, change in attribution, or the end of a road. The geometry of a RoadNode is coincident with the end of related links.

• MotorwayJunction – This is a point feature representing the generalised location of a motorway junction. It provides information on the motorway number and the junction number, for example M42 J2. Where two motorway junctions meet, for example, M3 J2 and M25 J12, there will be two MotorwayJunction features, one representing each junction.

Feature counts

Product issues and enhancements

GeoPackage format changes from April 2023

We have updated some of our products available in GeoPackage format to align with Open Geospatial Consortium (OGC) standards and to fix various formatting inconsistencies. Full details of the changes for OS Open Roads GeoPackage format can be found below:

• Layer names – The following layer names have changed from title case to snake case:

• Constraints – The following constraints have changed from title case to snake case:

• Attribute names – The following attribute names have changed from camel case to snake case:

• Column name – The geom column name has changed to geometry.

• Data types – The Length attribute has changed data type from Integer to Real.

• Attribute order – The attributes in the RoadLink layer have changed order:

• Identifier changes – Prior to April 2023, identifiers were prefixed with ‘id’. From April 2023, identifiers will no longer have the prefix ‘id’ (for example, id7F880726-8ADE-4952-B497-A54FE987C8F1 is now 7F880726-8ADE-4952-B497-A54FE987C8F1).

Next release

The next release of OS Open Roads is scheduled for October 2024.

Motorway junctions are represented by a MotorwayJunction feature.

The following table lists the attribution the MotorwayJunction feature can have, and details the definition, data type, length (where applicable), and multiplicity of each attribute.

MotorwayJunction attributes

A feature that represents the numbered motorway junction.

id

Unique identifier. For MotorwayJunction, this is a GUID, which is not persistent.

• Attribute name: id

• Type: CharacterString

• Length: 38

• Multiplicity: [1]

geometry

The location of the node.

• Attribute name: geometry

• Type: GM_Point

• Multiplicity: [1]

junctionNumber

The Motorway junction number designated by the national authority (Department for Transport), for example, M3 J9. Note: Where two Motorway Junctions meet, there are two features, for example, M3 J2 and M25 J12.

• Attribute name: junctionNumber

• Type: CharacterString

• Length: 12

• Multiplicity: [1]

This section describes the three features available in OS Open Roads. The attributes associated with these feature types are listed below along with a brief description of their data properties.

Feature type attribute information

Name and Definition

The name of the attribute and what it is describing.

Data type

The nature of the attribute, for example a numeric value or a code list value.

Multiplicity

Describes how many times this element is expected to be populated in the data. An attribute may be optional or mandatory within the product. These are denoted by:

• ‘1’ – There must be a value.

• ‘2’ – There must be two values.

• ‘n’ – There may be one or more values.

• ‘0’ – Population is optional.

Association

Identifies the relationship between features. These relationships are by reference only and the value will be the identifier of the referenced feature.

The RoadLink feature is a generalised representation of the road network alignment. RoadLink features are split in the following circumstances:

• Where the classification changes.

• Where the name changes (or ceases to apply).

Where there is a junction or roundabout at the same physical level.

The following list outlines the attributes a RoadLink feature can have, and details the definition, data type, length (where applicable), and multiplicity of each of these attributes.

RoadLink attributes

A feature which represents a part or all of a named or numbered road.

id

Unique identifier. For RoadLink this is a GUID, which is not persistent.

• Attribute name: id (GML), identifier (ESRI Shapefile), id (GeoPackage), id (VectorTile)

• Type: CharacterString

• Length: 38

• Multiplicity: [1]

centrelineGeometry

The geometry that represents the centreline of the link.

• Attribute name: centrelineGeometry

• Type: GM_Curve

• Multiplicity: [1]

fictitious

Indicator that the centreline geometry of the link is a straight line with no intermediate control points – unless the straight line represents the geography in the resolution of the data set appropriately.

• Attribute name: fictitious (GML), fictitious (ESRI Shapefile), fictitious (GeoPackage), Not provided (VectorTile)

• Type: Boolean

• Length: 5

• Multiplicity: [1]

roadClassification

Road classification uses a common system of route numbering, which is centrally administered for England and Wales by the Department for Transport. In all other respects, roads classification is a devolved matter outside of England.

• Attribute name: roadClassification (GML), class (ESRI Shapefile), road_classification (GeoPackage), road_classification (VectorTile)

• Type: RoadClassificationValue

• Length: 22

• Multiplicity: [1]

roadFunction

A alternative classification of the Road based on its usage.

• Attribute name: roadFunction

• Type: RoadFunctionValue

• Length: 30

• Multiplicity: [1]

formOfWay

A description of the RoadLink based on its form or function.

• Attribute name: formOfWay

• Type: FormOfWayValue

• Length: 50

• Multiplicity: [1]

roadClassificationNumber

The official road number assigned by the appropriate authority. Note: This includes at least one letter. For example, ‘A329(M)’.

• Attribute name: roadClassificationNumber

• Type: CharacterString

• Length: 10

• Multiplicity: [0..1]

name1

The name of the RoadLink. Note 1: Where a road has a name in more than one language, this attribute will be the Welsh or Gaelic version. Note 2: Where a feature has more than one name, the language of each name is provided as a three-digit ISO 639-2 code ('eng', 'cym', 'gla').

• Attribute name: name1

• Type: LocalisedCharacterString

• Length: 150

• Multiplicity: [0..1]

name2

The alternative name of the RoadLink, if any. Note 1: Where a road has a name in more than one language, this attribute will be the English version. Note 2: Where a feature has more than one name, the language of each name is provided as a three-digit ISO 639-2 code ('eng', 'cym', 'gla').

• Attribute name: name2

• Type: LocalisedCharacterString

• Length: 150

• Multiplicity: [0..1]

roadStructure

Identifies if this section of road passes through or over a physical structure, such as a tunnel or bridge.

• Attribute name: roadStructure

• Type: RoadStructureValue

• Length: 14

• Multiplicity: [0..1]

length

The calculated length of the RoadLink in metres.

• Attribute name: length

• Type: Measure

• Length: 10

• Multiplicity: [1]

loop

Indicates if the RoadLink feature connects back on itself by having the same start and end roadNode.

• Attribute name: loop

• Type: Boolean

• Length: 5

• Multiplicity: [1]

primaryRoute

States if the RoadLink forms part of the primary route network.

• Attribute name: primaryRoute

• Type: Boolean

• Length: 5

• Multiplicity: [1]

trunkRoad

States if the RoadLink forms part of the trunk road network.

• Attribute name: trunkRoad

• Type: Boolean

• Length: 5

• Multiplicity: [1]

startNode

The node coincident with the first vertex of the geometry attribute.

• Attribute name: startNode

• Length: 38

• Multiplicity: [1]

endNode

The node coincident with the last vertex of the geometry attribute.

• Attribute name: endNode

• Length: 38

• Multiplicity: [1]

roadNumberTOID

Identifier of the Road feature that holds the information about the road classification number the RoadLink forms part of in the OS MasterMap Highways Network product.

• Attribute name: roadNumberTOID

• Length: 20

• Multiplicity: [0..1]

roadNameTOID

Identifier of the Road feature that holds the information about the road name the RoadLink forms part of in the OS MasterMap Highways Network product.

• Attribute name: roadNameTOID

• Length: 20

• Multiplicity: [0..1]

OS Open Roads is a topologically-structured link-and-node road network of Great Britain. The links represent an approximate central alignment of the road carriageways and include all classified and unclassified roads that make up Great Britain’s road network.

OS Open Roads is a generalised product which is automatically derived from Ordnance Survey large-scale data. Generalisation is the process of reducing the scale and complexity of the data whilst maintaining the important elements and characteristics of the features. The appropriate product scale is 1:25 000, with a recommended viewing scale range of 1:15 000 to 1:30 000.

Available formats

OS Open Roads is supplied in the following formats:

• Geography Markup Language (GML): A national vector dataset in GML version 3.2.1 Simple Features Profile – Level 1.

• Shapefile: A national vector dataset in ESRI shapefile (.shp).

• GeoPackage: A national vector GeoPackage (.gpkg) file.

• Vector tiles: A national vector tiles file (MBTiles).

Identifiers

Each feature has a unique identifier. The identifier property name, which holds the feature's unique identifier, differs for each format:

• GML: gml:identifier property.

• Esri shapefile: identifier property.

• GeoPackage: id property.

Adherence to standards

OS Open Roads is based on the INSPIRE Transport Networks Road application schema, which is based on the ISO/TC 211 family of open standards.

Extending the INSPIRE specification

• OS Open Roads extends the INSPIRE specification with an additional feature type, MotorwayJunction.

• The OS RoadLink feature type extends the INSPIRE RoadLink feature type with a number of additional properties.

UML diagram and table conventions

The data structure is described by Unified Modelling Language (UML) class diagrams and accompanying tables containing text. The UML diagrams conform to the approach specified in ISO 19103 - Conceptual schema language and ISO 19109 - Rules for application schema, as adopted by INSPIRE.

Colour conventions are used in the diagrams and tables to distinguish the INSPIRE specification from the additional properties that have been added in the Ordnance Survey specification. In the UML diagrams, classes from the INSPIRE data specification are grey, whereas classes in the Ordnance Survey specification are orange. All code lists are blue and enumerations are shown in green. The tables which follow later in this technical specification use orange for feature types, blue for code lists, and green for enumerations.

Lexical conventions

• Class names are conceptually meaningful names (singular noun) in UpperCamelCase.

• Class names end in Value when the class is assigned the stereotype <<CodeList>> or <<Enumeration>>.

• Property names (attributes and associations) are in lowerCamelCase.

Stereotypes

The following stereotypes are used on UML elements:

Relationships and associations

There are four key types of relationship that can be defined between classes, only the following two exist in OS Open Roads:

1. Generalisation/specialisation – This is used to denote either:

   • An extension relationship - The target class represents the same real-world phenomenon. It has the same name as the class it extends. It simply includes additional properties. OR

   • A sub-typing relationship - The target class defines a specialised sub-type of a parent feature, for example, a TransportNetwork is a sub-type of a generic Network class.

2. Directed association – This is used to denote relationships between features. These relationships are by reference only (that is, they are implemented by a property whose value is the identifier of the related feature or object). The directed end is assigned a name that describes the relationship and a multiplicity.

Index

This technical specification includes the following sections:

• Product structure

• Feature types

• Code lists and enumerations

• GML overview

• ESRI shapefile overview

• GeoPackage overview

• Vector tiles overview

RoadNode features are added at the start and end of every . Where roads connect at the same level, a single RoadNode feature is captured.

The following table lists the attribution the RoadNode feature can have, and details the definition, data type, length (where applicable), and multiplicity of each attribute.

RoadNode attributes

A point representing either the start or end of a highway, or connectivity between two or more RoadLink features.

id

Unique identifier. For RoadNode, this is a GUID, which is not persistent.

• Attribute name: id

• Type: CharacterString

• Length: 38

• Multiplicity: [1]

formOfRoadNode «voidable»

Description of the function of a road node in the road transport network.

• Attribute name: formOfRoadNode «voidable»

• Type: FormOfRoadNodeValue

• Length: 20

• Multiplicity: [1]

geometry

The location of the node.

• Attribute name: geometry

• Type: GM_Point

• Multiplicity: [1]

OS Open Roads consists of three core features:

1. RoadLink – A feature which represents all or part of a road.

2. RoadNode – A feature which represents the end of the network, a change in attribution, or a junction.

3. MotorwayJunction – A feature which provides junction information along roads classified as a Motorway.

Features are provided as a FeatureCollection.

This product was built with the INSPIRE Transport Networks Data Specification as a basis, which results in the product inheriting attribution from INSPIRE. An overview of the product structure is detailed below, which highlights the inherited INSPIRE feature types and attribution. Note that properties of the INSPIRE specification which are voidable are not included in the image below or the subsequent tables. For information on the INSPIRE properties omitted from this product, please see the .

However, shapefile attribute naming is different due to the 11-character limit for attribute names in the shapefile format. Attribute mappings between the formats are provided in the , , and pages.

A code list is a controlled set of values for a free text data type which can be extended. This section identifies the code lists used within OS Open Roads and describes their values.

OS Open Roads is supplied as an Esri shapefile. The shapefile format is an open specification format to store geometry and attribute information about spatial features that is developed and maintained by Esri.

Attribute mapping

The naming of attributes in GML and Esri shapefile is different; in shapefile attribute names are limited to 11 characters. The tables in the following sections map GML attribute names to their equivalent names in shapefile.

The RoadLink feature is attributed with a roadFunction with a data type of RoadFunctionValue. The following table lists the codes which are used to populate this field and gives a description for each code.

Code List: RoadFunctionValue

The RoadNode feature is attributed with a RoadNodeCategory with a data type of TransportNodeTypeValue. The following table lists the codes which are used to populate this field and gives a description for each code.

Code List: FormOfRoadNodeValue

Functions of road nodes within Euroroads.

http://inspire.ec.europa.eu/codelist/FormOfRoadNodeValue

Classification of roads exists to ensure that there is a feasible, logical road network throughout the country. Road classifications should be set to take into account the traffic management goals and road categorisation approach of the local highway authority (LHA).

The RoadLink feature is attributed with a roadClassification with a data type of RoadClassificationValue. The following table lists the codes which are used populate this field and gives a description for each code.

Code List: RoadClassificationValue

The RoadLink feature is attributed with a formOfWay with a data type of FormOfWayValue. The following table lists the codes which are used to populate this field and gives a description for each code.

Code List: FormOfWayValue

Code List: RoadStructureValue

GeoPackage (.gpkg) is defined by the Open Geospatial Consortium (OGC) as an open, non-proprietary, platform-independent, standards-based data format for geographic information systems (GIS). It is designed to be a lightweight format that can contain large amounts of varied and complex data in a single, easy-to- distribute and ready-to-use file. GeoPackage is natively supported by numerous software applications.

GeoPackage offer users the following benefits:

• The single file is easy to transfer and offers the end-user a rich experience.

• Attribute names are not limited in length, making the format user friendly.

• The file size limit is large at 140 TB.

• It supports raster, vector and database formats, making it a highly versatile solution.

• It is an OGC standard.

• In most cases, it is a plug-in-and-play format.

For further information on GeoPackage, please see the GeoPackage website.

Attribute mapping

The naming of attributes between GeoPackage and GML is very similar as neither format limits the number of characters for an attribute name. The following tables map the GML attribute name to the GeoPackage attribute name.

The RoadLink feature is attributed with a roadStructure with a data type of RoadStructureValue. The following table lists the codes which are used to populate this field and gives a description for each code.

This section describes the GML format for OS Open Roads. We recommended you read this in conjunction with the Open Geospatial Consortium’s (OGC), OpenGIS® Geography Markup Language Encoding Standard v3.2.1.

The XML specifications that GML is based on are available from the World Wide Web Consortium (W3C) website: https://www.w3.org/XML/.

Information about Unicode and UTF-8, the character encoding that we use, is available on the Unicode Consortium website: http://www.unicode.org/.

Schema overview and location

XML schemas are used to define and validate the format and content of the GML data. The GML v3.2.1 standard provides a set of schemas that define the GML feature constructs and geometric types. These are designed to be used as a basis for building application-specific schemas which define the data content.

The Ordnance Survey application schema, OSOpenRoads.xsd, which is referenced by the data, is available on the OS Open page of the XML file resources section of our website.

The OS schema imports the INSPIRE Transport Networks Data Specification, which in turn imports the GML 3.2.1 schemas. These in turn import schemas produced by the W3C, which are available from the W3C website at: http://www.w3.org/XML/1998/namespace.html.

All of these schemas are defined in XML Schema Definition (XSD) language, as defined by the W3C.

The OS application schema uses the XML namespaces detailed in the table below. A link to each definition is provided in the last column.

Simple Features Profile – Level 1

OS Open Roads conforms to the GML 3.2.1 Simple Features Profile – Level 1.

GML is designed to support a wide variety of capabilities, ranging from simple contextual mapping to products that include complex geometric property types, and even spatial and temporal topology. The GML

1. Simple Features Profile defines a restricted subset of GML, which allows for greater interoperability.

Stylesheets

Predefined stylesheets for OS Open Roads are available for download from: .

• To download a zip containing all stylesheets, navigate to Code > Download Zip.

OS Open Roads is supplied as a national vector tile set in a single MBTiles file. This is a lightweight set of tiles that are efficient and fast to render in your software, provide high-resolution data and give a seamless experience when zooming in and out. The data is supplied in Web Mercator projection (ESPG:3857).

Attribute mapping

The naming of attributes between vector tiles and GML file is very similar as the vector tiles set within the MBTiles file is not limited in the number of characters for an attribute name. The tables included here map the GML attribute name to the attribute name in the vector tiles.

Vector Tiles schema

The vector tiles schema, as well as the attribute zoom levels, is detailed in the following three tables. The Zoom levels columns indicate whether or not the specified layer and attribute are displayed within that zoom level (Y – yes, N – no).

Motorway Junction Layer

Road Link Layer

Road Node Layer